Sizing of rayon



factory degree.

Patented 12, 1939 SIZING 0F RAYON Ernst von- Lippmann, Chemnitz, Germany, as-

signor to'Bohme Fettchemie-Gesellschaft m. b. 11., Chemnitz, Germany, a corporation of Germany No Drawing. Application December 24, 1936, Se-.-

rial No. 117,657. In

8 Claims.

This invention relates to the sizing of. rayon Y and more particularly to the treatment of rayon threads, yarn, skeins and the like, with a novel sizing agent which may be described broadly as highly acetylated monosaccharides and disaccharides.

Many susbtances have heretofore been used or suggested for use in the sizing of rayon butnone of them is completely satisfactory; The agents most frequently employed up to the present time include linseed oil sizes and organic colloidal subtances such as starch, glue, rubber gelatin, casein and. lime, resin and resin soaps, and in some cases with the addition of fats, oils, fatty acids, sulfonated oils waxes or paraflln. Prior workers have .suggested that alkali 'ethers of cellulose, particularly methyl cellulose, may be used alternatively for this purpose. Those sizes containing oils bind the rayon threads very satisfactorily, but the threads produced have the disadvantage that if they are stored for an extended period, it is difficult and in some cases impossible to remove completely the size from the fibers. Also, in some instances, the oil sizes due to their acidity. characteristics sometimes injure the flbers. V

When thesizing is effected through the use of fats, waxes and the other above mentioned substances, the threads are not bound to a satis- When the fibers are sized with water insoluble methyl cellulose, satisfactory binding is not obtained and besides such treating agent must be removed from the yarn by treatment with an organic solvent.

The primary object of the instant invention is to provide a new class or sizing agents which when appliedv to rayon gives optimum binding qualities, and leads to a sized ead which is unaffected by storage over extended periods and is removable with facilityand with a minimum of expense.

- The sizing agents employed'in accordance with the present invention may be referred to collectively' as highly acetylated saccharides having not more than two monosaccharide radicals in the molecule. The saccharide' may be either an aldose or a ketose ora non-reducing saccharide and may. contain fromfive to twleve carbon atoms.

The instant invention is, independent ofthe method by which the acetyl derivatives of the saccharide are obtained, for several suitable methods are known. The only requirement is that the saccharide -be either whollyor almost wholly. esterified by the introduction of acetyl Germany December 24, I

groups at the hydroxyl radicals of the saccharide I molecule. Suitable compounds include the tetraand penta-acetyl derivatives of the monosac- I charides and the hexaand octa-acetyl derivatives of the disaccha'rides.

These-agents are applied to the rayon threads or skeins by contacting the same with a. solution of the acetylated saccharide until the rayonhas absorbed or adsorbed a suflicient quantity of the solution or acetyl saccharide. Thereafter, the excess solution is' removed as by centrifuging and the rayonis driedin the usual manner. I

Satisfactory solvents for forming the solutions of the acetylated saccharides include organic sol vents such as pyridine; benzine, benzol and its homologues, and halogen hydrocarbons such as trichlorethylene and carbon tetrachloride.

The action of the acetylated saccharides of the instant invention may be supplemented by. other agents including sizing agents to improve the feel of the rayon or the binding of the threads. Suitable agents include fats, waxes, vegetable or animal oils, mineral oils, sulfonated oils, higher 'molecular fatty alcohol sulfonates, which substances may be applied separately as in the form ,of oils as such, or'may be applied in admixture with the acetylated sugars of the present invention in suitable'solvents as herein described.

The sizing agents of the present invention .possess many advantages over prior substances used for this purpose. They are-colorless and do not have a tendency to decompose through oxidation during storage. Therefore, -the fibers sized in the manner described herein are not detrimentally affected by storage before thesame is woven or treated for the removal of the size. The acetylated monoand disaccharides are ex.-

cellent binders for the threadsand the results vantages resulting from the use of the acetylated saccharides herein described lies in the fact that such -sizing agents may be removed from the fibers by merely treating the same with hot water. The-reason that these substances can be removed from the threads with such extraordi- Y nary ease lies in certain cases in the relatively low melting point of the acetylated monoand disaccharides.- The removal is accomplished through the action of the hot water in melting the sizing agent, the melted agent being easily dispersed in the water. 7 When fats, waxes or oils and the like are empl yed inaddition to the acetylated sugars, it is necessary to employ in the liquid used for the removal of the size organic solvents, soap or synthetic washing agents, such as fatty alcohol sulfonates and condensation products of the taurines or suifonic acid derivatives of hydroxy ethane fatty acids (i. e. Igepon"). An addition of a weakly alkaline agent, such as a small amount of soda or borax, may also be used to advantage in the liquid employed for the removal of the sizing agent, particularly when difllcultly saponifiable materials are present in the size, or when the materials are contaminated with impurities which may have been obtained in an accidental manner, such, for example, as spots of lubricating oil, or of rust or of soot.

The sizing agents of the present invention may be removed if desired by means of agents other than water, for example, by means of organic solvents such as pyridine, hydrocarbons such as benzine and benzol, or halogen hydrocarbons, for example, trichlorethylene. The acetylated saccharides contained in solutions formed by the use of such solvents may be recovered by evaporating and concentrating the used solution in known manner and employed again in a further sizing operation of additional rayon. Through the recovery of the used size and reuse of the same, the present process may be operated in a very economical manner. 4

The process may be carried out in accordance with the following examples:

Example 1 Viscose rayon skeins are treated at C. for about twenty minutes in a solution of 50 grams per liter of octa-acetyl-saccharose in trichlorethylene, during which time the skeins are continually agitated. Thereafter, the 'skens are removed, centrifuged and dried in a drying chamher at 40-45" C. The yarn treated in this manner possesses a very good thread closure or is very satisfactorily bound and also possesses a relatively soft or non-harsh feel which is in an excellent condition for weaving.

The sizing agent, after weaving, may be removed from the fibers by treating the same with water at 80-90 C. for a period of one hour. Since the size can be removed without difllculty in aqueous solutions, the operator may eliminate the separate step for removing the size, and thus may dye the material directly, since the finish is not affected in the preliminary treatments but is wholly removed in the dye bath.

Example 2 Cuprammonium rayon skeins are treated with a solution of 75 grams per liter of penta-acetyl glucose in a commercial pyridine mixture at a temperature of C. for a period of thirty minutes, during which t me the skeins are agitated in the solution. After centrifuging and drying at a temperature of 60-'l0 C., sized yarn is obtained having properties similar tothat described above in Example 1, but the yarn treated in the manner of this example has a particularly soft feel.

Example 3 Viscose rayon skeins are treated at a temperature of C. for a period of thirty minutes in a bath composed of a mixture of 10 grams of penta-acetyl glucose and 5 grams of olive oil which have been dissolved in'one'.liter of trichlorethylene. The skeins are agitated during the treatment and upon its completion, they are :removed, then centrifuged and finally dried at 40-50 C. After the yarn treated in this manner has been formed or woven, the size may be removed by a treatment with benzine, benzol, toluol, trichlorethylene, carbon tetrachloride or pyridine. The mixture of penta-acetyl glucose and olive oil can be recovered from the solvent and used again in the treatment of another batch of rayon. The treatment described in the above examples is satisfactory for the sizing of acetate rayons, as well as for the sizing of viscose and cuprammonium rayons. Furthermore, other acetylated saccharidesmay be employed in the processes of the above examples, for example, the penta-acetate derivatives of fructose and galactose, which compounds may be suitably obtained by complete acetylation of compounds obtained from invert sugar or lactose and other analogous compounds yielding wholly or almost wholly acetylated saccharides.

From among the novel sizing agents of the present invention and mixtures of the same with other sizing agents, operators of the process may choose the agent or combination which best suits their purpose, their choice depending upon the characteristic properties desired in the rayon treated.

It should be understood that the present invention is not limited to the specific examples hereinabove set out, but that it extends to all compounds and procedures within the scope of the terms of the appended claims.

Example 4 Viscose rayon skeins are treated at about 40 C. for a period of thirty minutes in a solution of grams per liter of octa-acetyl-lactose in trichlorethylene, during which time the skeins are agitated in the solution. Thereafter they are removed, centrifuged and dried at about 50 C. The properties of the yarn treated in this manner are similar to those described above in Example 1. After the forming or weaving of the yarn the sizing agent may be removed by treating the fabric with water at 90-95" C. for a period of one 110111;

Example 5 Viscose rayon skeins are treated at 40-50" C. for a period of thirty minutes in a solution of 50 grams per liter of octa-acetyl-cellobiose in carbon tetrachloride. The skeins are agitated during the treatment and upon its completion, they are removed, centrifuged, and dried at about 50 C. The sizing is removed by treating the yarn after the forming or weaving of the same with water of 90-95 C. in which 3 grams of sodiumlauryl sulfate per liter have been dissolved.

I claim:

1. The process of treating rayon threads, yarns,

skeins, and the like to effect binding in preparation for weaving which comprises sizing said rayon by coating the same with a stable waterinsoluble highly acetylated saccharide having not more than two monosaccharide radicals in the molecule and after weaving removing said size;

2. The process of treating rayon threads, yarns", skeins, and the like to eflect binding in prepara tion for weaving which comprises sizing said rayon by coating the same bythe application of a solution of a stable water-insoluble highly acetylated monosaccharide and after weaving removing said size.

3. The prpcess of treating rayon threads, yarns, skeins, and the like to effect binding in preparation for weaving which comprises sizing said rayon by coating the same by the-application of aneaaav tylated disaccharide and after weaving removing said size.

4. The process of treating rayon threads, yarns, skeins, and the like to eiiect binding in preparation for weaving which comprises sizing said rayon by contacting the said rayon with a solution of a stable water-insoluble highly acetylated saccharide having not more then two monosaccharide radicals in the molecule until the surfaces of the same are coated with the saccharide, removing excess solution, drying the same and after weaving removing said size.

5.- The process of treating rayon threads, yarns, skeins, and the like to eflect binding in preparation for weaving which comprises sizing said rayon by coating the rayon with a solution of a stable water-insoluble highly acetylated saccharose and after weaving removing said size.

20 6. The process of treating rayon threads,'yarns,

skeins, and the like to effect bindingin preparation for weaving which comprises sizing said rayon by coating the rayon through the application of a solution of a stable water-inso1ubleoota-' acetyl-saccharose, and said size.

'1. The process of treating rayon threads,,yarns', skeins, and the like to effect binding in preparation for weaving which comprises sizing said rayon by coating the rayon by the application of a solution of a stable water-insoluble highly acetylated glucose and after weaving removing said size.

-8. The process of treating rayon threads, yarns, sk'eins, and the like to eflect binding in preparaafter weaving removing tion for weaving which vcomprises sizing saidrayon by coating the rayon by application ofa solution of a stable water-insoluble penta-acetylglucose, and after weaving removing said size.

ERNST VON LIPPMANN. 

